The present invention relates to a control system for a tool coupling and, more particularly, to such a control system for use on an excavator carrying an excavator bucket for determining the orientation and position of the bucket teeth. The control system may display orientation and position information to assist an operator in manually controlling the movement of the excavator bucket, or it may use this information to effect automatic control of the movement of the bucket in a desired manner.
Excavators have gained wide use for handling rocks, dirt, logs, tree stumps and the like at job sites, as well as for performing a variety of excavation tasks, including those that require fairly precise movement of an excavator bucket. Other tasks to which an excavator can be applied are best performed with a different tool carried by the excavator, such as for example a grappling device. An excavator typically has a dipper stick which is attached at one end to a boom that extends from the excavator frame. The other end of the dipper stick may be attached to the tool, such as for example a grappling device or an excavator bucket, by means of a connector configured for the task. Such a connector, as shown in U.S. Pat. No. 4,958,981, issued Sep. 25, 1990, to Uchihashi can provide a way of rotating the tool at the end of the dipper stick under hydraulic control as desired so that the tool can be moved precisely into desired orientations under the control of the excavator operator. The connector of the Uchihashi patent only permits the rotation of the tool about a single axis. More advanced connectors have been developed and marketed by companies, such as Indexator AB, of Vindeln, Sweden under the mark Rototilt. The Rototilt connector includes one or two additional hydraulic cylinders which are connected to the rotatable portion of the connector and which permit the rotatable portion of the connector to be tilted from side to side. Since the connector and the tool may be pivoted about a third axis by the linkage arrangement at the end of the dipper stick, the tool can be maneuvered into almost any desired position and orientation without actually moving the excavator frame to a new location. Not only does this expand significantly the tasks that can be performed using the excavator, but it also facilitates changing the specific tools carried by the excavator.
With the added flexibility of such an arrangement for controlling movement of a tool, however, comes the complexity that results from the additional hydraulic cylinders and mechanisms that must be controlled simultaneously. A need exists for an arrangement for monitoring the position and orientation of a tool, such as an excavator bucket, when manipulated by a machine, such as an excavator, so that the control of the tool can be facilitated.